1. Field of the Invention
This invention pertains to the mounting of an electrically conductive rail system for providing power to electrically driven devices that move along tracks.
2. State of the Prior Art
Electrically conductive rail systems are widely used in industrial plants for providing power to drive movable hoists, monorail vehicles, and various types of trolley devices. In textile plants, for example, electrified rail systems are utilized to provide power for suction and blowing types of travelling cleaners for removing lint from machinery surfaces and from the floor.
An electrically conductive rail was typically made in the prior art by forming an elongate strip of metal into a modified "FIG.-8" configuration, with a flat longitudinally-extending medial portion of the elongate strip lying between rounded edge portions that are folded so as to form eyelets. A conductive rail of this type is typically encased in an electrically insulating sleeve having a longitudinally-extending opening that exposes the flat medial portion of the rail to contact with a shoe or other type of electrical conductor that slides thereon for providing power to an electrically driven device or vehicle. The electrically conductive rail enclosed in its insulating sleeve, or more typically a system comprising a plurality of such rails enclosed in their individual insulating sleeves, is mounted on a support structure so that the rail or rails extend generally parallel to a track or other pathway along which the electrically driven device or vehicle is to travel.
In mounting such an electrically conductive rail to a support structure in the prior art, it was usual to provide a resilient clip configured to grasp the insulating sleeve surrounding the rail in such a way that the exposed flat medial portion of the rail was oriented to permit sliding contact along the rail by an electrically conductive contact shoe of the device or vehicle to be driven. In the usual case, a plurality of such resilient clips were arranged parallel to each other and secured to each other by a bolt that passed through each of the clips. The means for positioning the resilient clips securely with respect to each other also served to fasten the clips together as a group to some sort of spacing means. Such a spacing means in the prior art usually was not an integral structure but rather typically comprised a plurality of spacing devices, with a separate spacing device being provided between each two adjacent clips. Each spacing device was separately secured, as by a bolt and nut, to the support structure.
A mounting assembly typical of the prior art for securing an electrically conductive rail system to a support structure is illustrated in FIGS. 1 and 2. As seen in FIG. 1, resilient clips 10, 11 and 12 are fixedly retained in spaced-apart proximity to each other by means of a bolt 15 and nut 16 and spacing members 20 and 21. The resilient clips 10, 11 and 12 are interchangeable with each other, and each clip is configured to grasp an insulating sleeve enclosing an electrically conductive rail. The clips 10, 11, and 12 retail the rails parallel to each other.
Each of the resilient clips 10, 11 and 12 has a generally U-shaped cross-sectional configuration, with the upper portions of the arms of each clip being curved to provide facing concave surfaces for grasping an insulating sleeve enclosing a conductive rail. The bolt 15 passes through apertures in the vertical lower portions of the arms of each of the clips 10, 11 and 12. The adjacent clips 10 and 11 are spaced apart from each other by the spacing member 20, and the adjacent clips 11 and 12 are spaced apart from each other by the spacing member 21. The spacing members 20 and 21 are secured to a support structure 25 by nuts and bolts indicated by the reference numbers 30 and 31, respectively. The support structure 25 is typically an I-beam, which may be suspended from the ceiling, or mounted on the floor or on the casing of the machine.
The spacing members 20 and 21 are formed from relatively short strips of metal, which are folded so as to provide loops that are aligned with the apertures in the vertical lower portions of the arms of the clips 10, 11 and 12. The bolt 15 passes through the loop formed by each of the spacing members 20 and 21, each spacing member being interposed between two adjacent resilient clips. The spacing members 20 and 21 are shaped on their longitudinal edges so as to provide seats for the horizontal and lower vertical portions of the resilient clips 10, 11 and 12. In this way, the bolt 15 and nut 16 secure the clips 10, 11 and 12 to the spacing members 20 and 21; and the bolts 30 and nuts 31 secure the spacing members 20 and 21 to the support structure 25.
In FIG. 2, the prior art mounting assembly of FIG. 1 is shown in plan view. The bolts 30 that secure the spacing members 20 and 21 to the support structure 25 are visible adjacent both ends of each of the spacing members 20 and 21. The bolt 15, which secures the clips 10, 11 and 12 in proper disposition with respect to each other and with respect to the spacing members 20 and 21, is seen passing through the lower portions of the clips 10, 11 and 12 under loop portions of the interposed spacing members 20 and 21.
Thus, in the prior art rail mounting technique as illustrated in FIGS. 1 and 2, a single clamping means comprising the bolt 15 and nut 16 provided the entire clamping force for squeezing the resilient clips 10, 11 and 12, whereby the clips could grasp the electrically insulating sleeves enclosing the electrically conductive rails. The clips 10, 11 and 12 were not independently clamped, and any looseness that might develop in the grip of the nut 16 on the bolt 15 would affect the tenacity of the grasp of each of the clips 10, 11 and 12 on its respectively held sleeve and enclosed rail. Furthermore, in the prior art, the clamping means for enabling the clips 10, 11 and 12 to grasp the sleeves and enclosed rails securely was independent of the means for securing the clips 10, 11 and 12 to the support structure 25.